Biological Diversity 2001

Photo courtesy of the Darwin Foundation.

Kingdom: Animalia
Phylum: Echinodermata
Class: Holothuroidea




Conservation Organizations

Darwin Foundation
Conservation Group specifically concerned with the Galapagos Islands.

www.darwinfoundation.org

Secreteriat of the Pacific Community
Watchdog conservation organization for marine wildlife in the Pacific Ocean.

http://www.spc.org.nc

 

 

 

Beche-de-mere made from Holothuroidea scabra. Image courtesy of SPC.

 

 

Image courtesy of http://www.polaris.net/sui/jpinson/pml/gal/pepino/pepino.html
Author and date unknown.

 

 

Literature Cited

Charles Darwin Research Station. copyright 2000- 2001. www.darwinfoundation.org Home page. Accessed November 12, 2001.
www.darwinfoundation.org/marine/FAQcuke.html FAQ Page. Accessed November 12, 2001

Columbia Electronic Encyclopedia. copyright 2000. http://www.encyclopedia.com/articles/11634.html Articles Page.
Accessed November 12, 2001.


Environmental News Network. copyright 2000.
http://www.cnn.com/2000/NATURE/08/30/sea.cucumbers.enn/index.html Nature page. Accessed November 12, 2001.


Royal British Columbia Museum. copyright 1995. http://rbcm1.rbcm.gov.bc.ca/nh_papers/taxing.html Natural History Page. Accessed November 12, 2001.


Secreteriat of the Pacific Community. updated Oct. 29, 2001. www.spc.org.nc Home page.
http://www.spc.org.nc/coastfish/News/bdm/12/1.htm Beche-de-Mere January 2000 Newsletter. Stephen C. Battaglene.
http://www.spc.org.nc/coastfish/News/BDM/14/BDM14-05.htm Beche-de-Mere
May 2001 Newsletter. Priscilla C. Martinez.
http://www.spc.org.nc/coastfish/News/BDM/BDM7.pdf Beche-de-Mere
Newsletter.

http://www.spc.org.nc/coastfish/News/BDM/15/BDM15-01.htm Beche-de-Mere
Newsletter.

World Wildlife Fund. copyright 1995-2001. www.wwf.org Home page. Accessed November 12, 2001.


 

 

Holothuroidea

Introduction

Sea cucumbers (Holothuroidea) include more than 1100 species of marine organisms worldwide. They make up an ancient group; modern cucumbers are the results of 540 million years of evolution from their original appearance in the ocean (Lambert, 1995). These slug-like creatures suit their environment well. Their bodies are cylindrical, with a mouth and anus at opposite ends. Retractable tube feet and tentacles allow feeding and movement along the sea floor. When encountering a predator, sea cucumbers will commonly expel their organs as a distraction. They have a supply of backup organs and the ability to regenerate those that are lost (Columbia Electronic Encyclopedia, 2000).
The functions of sea cucumbers make them a crucial part of marine conservation movements. As large-scale detritus feeders, they are responsible for recycling up to 90% of the biomass on the ocean floor. The trade of sea cucumbers occurs consistently in world markets. In the Galapagos Islands, mass quantities of sea cucumbers are traded each year in dry form to Asian markets where they are considered delicacies and remedies for ailments and thought to have aphrodesiacal qualities (Environmental News Network Staff, 2000).


Conservation Status

No species of sea cucumber is listed on the ICUN red list. Upon examining the criteria, it is possible they have been omitted due to lack of research, or because although there are species threatened in a regional area but no species' global population is threatened.

Image courtesy of The Darwin Foundation

Conservation Issues

In many Asian markets, the sea cucumber has historically been fished and consumed as a delicacy, and in recent times the demand has skyrocketed. More and more, the large world markets - Japan, Hong Kong, Taiwan, and Singapore - which export to smaller consumer markets, have turned to fisheries outside of Asian waters as their own stocks have become depleted (Conand 1999). Of the approximately 1250 species of Holothuroidea worldwide, only a handful are commercially exploitable or are so at this time (nearly all of these are from the order Aspidochirotida), and these are suffering from the pressures of commercial fishing operations.

Some of the major fisheries that have been the focus of recent attention are those off the coasts of Baja California, Eastern Russia, and the Galapagos Archipelago. In Baja California, harvesting of the sea cucumber Isostichopus fuscus (Family: Stichopodidae, Order: Aspirochirotida) for export to Asian markets rose very sharply between between 1985 and the mid nineties, and in May of 1994 they were declared in danger of extinction by the National Institute of Ecology of Mexico (Castro 1995). The sessile and therefore easily harvested. Cucumaria japonica (Family: Cucumaridae, Order: Dendrochirotida) has historically been fished in the seas of Eastern Russia for both food and cosmetic products. Like other species, these cucumbers contain chemicals called triterpine glycosides which have may possible commercial uses, and fishing - done by bottom trawling - is increasing annually well beyond the legal 50 ton catch limit (Levin 1995).

Overfishing of sea cucumbers very often correlates with local socioeconomic problems. In 1989, sea cucumber fishermen from mainland Ecuador naming themselves pepineros arrived in the Galapagos and began setting up operations, the fisheries off the coast of Ecuador being nearly depleted. There was no sound biological basis for establishing a fishery there, nor any management plan enacted that might have regulated the fishing practices of the pepineros (Martinez 2001). Populations of the sea cucumber Stichopus fuscus (Family: Stichopodidae, Order: Aspirochirotida) became dramatically reduced almost immediately, and this coupled with the increased migrations of people to the Galapagos prompted a ban on all harvesting of sea cucumbers. Illegal fishing continued, however, and in early 1994, the pepineros began slaughtering tortoises and sea lions as a protest against the ban, and under pressure from environmental groups the ban was lifted. It was not until Ecuador passed the Galapagos Marine Management Plan in 1999 that harvesting of sea cucumbers became regulated under a concrete legal and conservation framework. The successive fishing seasons have shown marked increases in sustainability, though problems with the pepineros killing and kidnapping tortoises continue (Martinez 2001).

Research into sea cucumber reproduction has shown that because they are broadcast spawners, populations with low density tend to increase only slowly. In the Torres Strait, where overfishing has reduced populations of sandfish or Holothuroidea scabra (Family: Holothuroidea, Order: Aspidochirotida), the Australian government is exploring the possibility of 'seeding' depleted fisheries with hatchery-raised juveniles, but as yet has not begun a wide scale program (D'Silva 2001). Sandfish have proved an important candidate for research into artificially repopulating fisheries due to its hardy and resilient larvae, and more so because it is one of the most highly prized and thus overfished of the sea cucumbers (Battaglene 1999).

The dangers in losing large numbers or even entire populations of sea cucumbers is that within their ecosystems they are some of the primary detritus feeders, consuming and pulverizing organic matter so that it may be easily broken down by bacteria. Without them, the quality of the substrate may be severely reduced; in some areas of the world, overfishing of sea cucumbers has caused the hardening of the sea floor, leaving it uninhabitable to many other bottom-dwelling organisms (Darwin Foundation 2001). Biodiversity in many marine ecosystems is thus heavily dependent on the presence of healthy populations of sea cucumbers.

Image courtesy of The Darwin Foundation

 

Authors: Lucy Beirne, Katie Fitzmier, Matt Miller
Creation/revision date: November 29, 2001


Acanthaster planci Apis mellifera Capybara Chimpanzee Danaus plexippus Exciting Cephalopods Green Sea Turtle (H-R,K) Green Sea Turtle (B,M,C) Green Serpent Star Holothuroidea Hyenas Latimeria chalumnae Mudpuppy Northern Leopard Frog Pink Seafan Salamanders Scyphozoa Tuatara

This website is part of a Biology 26 class project on the conservation of global biodiversity.



Earlham · Biology Department · Biology 26 : Biological Diversity

Copyright ©-2001 Earlham College. Revised 1 October 2001. Send corrections or comments tobeirnlu@earlham.edu fitzmka@earlham.edu or millema@earlham.edu